Signal intensity responsive gaseous discharge device gate



April 11, 1950 w. LYONS 2,503,958

SIGNAL INTENSITY RESPONSIVE GASEOUS DISCHARGE DEVICE GATE Original Filed Feb. 20, 1945 2 Sheets-Sheet 1 LYONS SIGNAL INTENSITY RESPONSIVE GASEOUS DISCHARGE DEVICE GATE April 11, 1950 2 Sheets-Sheet 2 Original Filed Feb. 20, 1945 INVENTOR 75,? lac/vs. g

ATTORNEY Patented Apr. 11, 1950 ii STATES? EL'NT OFFICE} SIGNAL INTENSITY RESPONSIVE GASEOUS DISCHARGE DEVICE GATE" Walter; Lyons; Bayside, N. Y.,: assignor to Radio. i

Corpcration of'Anierica, a corporation'of Delaware.-

Or'iginal application-February '20, 1945;Serial No.

'78;8='7'7; Di'videdand this application February 14;:1947ISe1ialN0-J 728,673

2 Claims.

This application; ewhich --,is-a division ofmy.

U.-.S. applicationyserial #578,877,- filed February 20;:1945, "rel-atesto relayingapparatus in gen-1'. eraL-sucli as might be used: in diversity systems in genera-1;.andzinzparticulari-to diversity receivers ofthe" type 'wherein'meansriswprovided at the various:receiverscto use. onlyrthe best received signalyandzrenderthe receivers responding to weaker signals 'inefiective to contribute to the output.

The ;main5- general =objectof my invention is improvedcontrolofzan alternating current chan:

nelzrepeater or gate::

The; present invention-has i been described as inchannel selecting conneetionsinca diversityreceiver system, :butrchas 0th el -"uses wobvious to those skilled the art.

In the" embodimenttdiscussed :three receivers are" arranged in:v triple diversity. 1'., The :receivrer outputs are to berso: usedthat: recording or'simiiar means: is controlledtby thestrongest signal;- which also renders ineffective 1therchannels wherein Weaker signalseppear.

In describing amy'invention. in detail; reference willbemadeto the"attachedadrawings wherein Fig. -1 illustrates'thezessential details: of 'the inter-r mediate .frequencycircuit connections. of three wave receivers in a diversity syst'ernarranged"in:

accordance with my invention,"

Fig. 2 is a rnodifi'cationx ofuthi arrangementrof Figt l; 'while s- Fig. 3 modification of :-the arrangements of Figs. 1 and 2.

Intermediate frequency output from. three antenna' radio; frequencywamplifiers; etc; #I'; #2

and ,are: supplied to-the primary -windingzofr; intermediate "frequency:transformers 4, *4 and 4' To further simplify, the disclosure; the novel 1 features-of the illustrated portion of receiver #l Will zbezdescribeda The description;'thereofcape-v plie's equally well to :the loth'erri-eceivers and-.sini-y ilar reference numerals primed: and double primed arerznsed to designate the elements" ni -channels 3 #2 and-#3 respectively. a

The intermediate frequency- :energy is supplied. totheinputgrid-Vfi of -a limiter tube stage 40,";-

whichin turn is used to d-rivea discriminator and detector operating atvthe intermediate frequency. The input circuits 2 and-.4 are- -tuneid-itovthe frequency of the intermediatefrequency energy supplied ,to the circuit 2....The cathode. of tube Hl is connected totgroundi-by-a cathodebiasinga resistor ,l 2 shunted by 3. radio frequency bypass-- condenser-,1 I, while the (grid direct current cir-. cuit. includes. a resistor i 3; shunted.- by a radio frequency bypassing condenser.

I2 and in resistor |3 dependingupontthezsignal strength. The negative potentialdeveloped; in, resistor l3 due to :gridrectification'is proportional-i to the signal strength,awhi1e for reasons pointed. out in detaiihereinafter; the positive potential-w developed in resistor 12 is inversely .pi oportional tothe signal strength.-

The anode of thetube-Hi isaconnected to a tuned circuit M. The inductance'of, the tuned-z circuit H is coupled'to:the-inductanceof a tuned-z circuitv i6 theterminals ofwhich are connected. to. diodes It and 1 20. A point on the :inductancew of the tuned circuit l6 is'connectedi-by a radioa frequency choke RFC towa point between;-resist, ances -24":and 26,"between the cathodes of .the diodes l8; and-2lix Thecondenser iii/connects the high potential .end of 'tuned-circuit-Mi-to a point on the inductance -16 -to-thereby couple intermediate frequency energy-appliedto' the circuits' I4 andalfi is*abo've=,or belowethexresonant In 4 the? embodiment? frequency of ;these circuits: described;:this energycis keyedsfromqa first free.-

quency on'one side of :theiresonants, frequency: toe a :second--,vfrequency .on:-ther-other--side of the resonant-frequency:as described-"above; z

The "output ofwthis discriminator vI-appearing, at-; thexpointz-A mayz-be treatedcasalternating current and this point-is connected'by an .altematingcur-r rent circuit including condenserMend-resistance Bit-to thecathode 407101? a tetrode 'I'hyraton;valve-=1 l This is :the :valve or repeater" to Joe. controlledin accordance with my-invention.

The alternatingucurrent signaleappearingiati.

- the (point A is prevented-from firing theH-tubecM- by inclusion of a condenser '42 :betweenthe con-q trol grid 43 of-zthis tube and the cathode 40. If; the tube 4 [is extinguished-changesin the cathode potential due to the alternatingicurrent'fed there to by resistance 32=-are,:also. applied by.condenser 42 to the controlugridcfl soflthat the .potential difference between the grid; '43 and the-cathodes 40'Edoes not materially change canditheratubelrere mains extinguished;

The cathode -.40'=--of tubfl 4| w is alsoseonnected On-the app1ica.-.-, 1 tion of signals a potential is developed-in. resistor.

to the cathode resistor I2 of the limiter stage it? in order to receive the otentials developed therein to strike or ignite the tube 4| When the potentials on the cathode grid and anode of tube 4| are properly related. This connection includes a resistor 37 which serves to prevent shorting the signal potential applied to grid 43 to ground by the capacitor across resistance I2. Ignition of the tube 4| causes the detected signal from the discriminator appearing at point A to be supplied to the load circuit tit. The anode 45 of tube 4| is connected by resistance R and load impedance 6|] to the positive terminal of a direct current source the negative terminal of which is grounded. The anodes 4, 45' and 4-5" are each coupled to the other by condensers C, C and C". The control grid 43 is connected to ground by resistance 47 to have essentially ground potential in order that the effective bias potential between grid 43 and the cathode til of tube 4| is such that the grid is always negative with respect to the cathode.

The firing potential in each channel, i. e., the positive potential applied from resistance |2 to the cathode 40 by lead 35 and resistance 31 is in versely proportional to the received carrier strengthdue to the negative potential built up across resistor l3 in the grid circuit by grid circuit rectification. The higher the signal applied in the circuit 2 the higher the negative potential on the grid 6. This serves to more or less decrease the plate current in tube H] as the sig nal amplitude increases, thus reducing current through resistor |2 and the positive potential developed across cathode resistor l2 and appearing at the cathode of tube 4|. The potential across resistor |2 is applied to the cathode 42! of the tube 4| as a striking or igniting potential. As the signal strength increases the potential at l2 falls as described above and the potential at 40 falls. This in turn results in efiectively making the potential of the grid 43 of gas tube 4| less negative and the tube strikes and passes signal to the load 60. Obviously, the channel re ceiving the strongest signal and applying the same to the tube H1 or Ill or NJ" will strike its Thyratron gas tube first. The characteristic of these gas tubes is such that the grid potential no longer controls discharge once the tube is fired.

Similar connections are made in the additional channels #2 and #3 including tubes 4| and 4!. The anodes 45, 45' and 45 of the tubes 4|, 4| and 4|" are mutually inter-connected by the capacitors C, C and C, the charging currents of which serve to blow out the discharges in the two tubes having higher control potentials impressed on their respective cathodes. Assume, for example, that the tube 4| has been struck and conducts current through the resistor R. The potential at the anode 45 end of this resistance R drops because of the heavy current flowing in R and this permits the condenser C and the condenser C to discharge the high direct current potential at anodes 45" and 45' so that current flows through resistances R and R and condensers C" and C through the impedance of tube 45 to lower the potentials on the anodes 45' and 45" to a point at which these tubes in the channels then receiving weaker signals are maintained extinguished or if ignited are blown out.

A portion of the total plate loads of the three Thyratrons 4|, 4| and 4|" is a common impedance across which the signal due to the strongest channel is available for output.

' It may be desirable to connect grid 46, i. e., the

4 shield grid to some point on resistance l2 by a lead 39 as shown in Fig. 2 instead of to the cathode of the tube 4| as shown in Fig. 1, to adjust the threshold value or firing point of tubes 4|, 4| and 4|". This connection also provides a convenient means to relatively adjust the potential of the three shield grids 46, 46 and 4b in order that tubes 4|, 4| and 4|" may be given similar operating characteristics if they do not inherently have such characteristics.

Making the grid 46 more negative reduces the value of the efiective negative potential on the grid 43 at which firing of the Thyratron takes place. Increasing the negative potential on the shield grid 46 will require the control grid to be more positive, i. e., less negative before firing takes place, and this in turn requires a stronger signal on cathode 40 for firing the tube. When considering this operation keep in mind that the potential across resistance I2 is inversely pro portional to the received signal strength.

The embodiment of Fig. 3 includes features of Figs. 1 and 2. The grid leak resistor i3 is con nected to ground instead of to the cathode of tube it as in Figs. 1 and 2. The operation of this part of this alternative embodiment to accornplish limiting in tube Ill and supply the control potential by lead 35 to the cathode 40 of the gate tube 4! is as in Figs. 1 and 2. Lead 39 serves the same purpose as lead 39 in Fig. 2.

In the description given above it is said that the alternating currents to be passed by the tubes 4|, 4! and 4|" are applied to the tube cathodes 44, 4d and 49 respectively, and that to prevent this alternating current from firing the tubes alternating currents of like phase are fed to the control grids 43, 43' and 43" respectively. Once a tube is fired its internal impedance is very low and it is correct to say that the alternating current voltages fed to the cathodes are passed by the tubes. Moreover, it is seen that the firing potentials applied to the cathodes fire the tubes because the cathodes become less positive as the carrier intensity grows, which is the same as making the grids less negative. The potentials developed across the resistances l2, l2 and i2" may be said to control the direct current potentials on the grids 43, 43 and 43". If desired the connections to the tubes M], It and ill" may be arranged to provide negative potentials which decrease with an increase in carrier strength, and use these potentials to control the potentials on the grids 43, 43' and 43".

As brought out in the specification the carrier of greatest intensity provides the best signal when demodulated and this signal is selected and passed along by using as the gating potentials the direct current developed in resistances l2, I2 and i2". These potentials are about inversely proportional to their carrier intensities, and it may also be said that these potentials are likewise about inversely proportional to the average amplitude of the alternating currents representing the signals and derived by demodulating the received carriers when the same are modulated in amplitude at the transmitter and detected by amplitude modulation detectors at the receivers, which alternating currents are applied to the grids and/or cathodes of the tubes 4|, 4| and 4|".

What is claimed is:

1. In an electrical Wave energy relay, a first tube having a control electrode to which said wave energy is applied and having also an anode and a cathode, a second tube of the gaseous discharge type having an output electrode and two other electrodes comprising a control electrode and a cathode electrode, an output circuit coupled to said output electrode, translating means coupling the anode of said first tube to the cathode of said second tube to supply translated electrical wave energy from said first tube to said second tube, means for preventing the translated wave energy applied to the cathode of said second tube from firing the same, means for developing a positive direct potential about inversely proportional to the strength of said wave energy, said last-named means including a resistance, connected in series in the anode-cathode circuit of said first tube, across which said potential is developed, means connected between the control electrode and cathode of said second tube to apply a desired bias therebetween, and connections from said resistance to said two other electrodes of said second tube to apply said potential therebetween as a firing potential.

2. In an electrical wave energy relay, a first 2o tube having a control electrode, an anode and a cathode, a second tube of the gaseous discharge type having an output electrode and two other electrodes comprising a control electrode and a cathode, an output circuit coupled to said output electrode, translating means coupling the anode of said first tube to the cathode of said second tube to supply translated electrical wave 5 in the anode-cathode circuit of the first tube, a

resistance connected between the control electrode and cathode of said first tube, means for developing a direct potential which is about proportional to the strength of said wave energy,

10 said last-named means including one of said resistances across which said potential is developed, means for establishing a bias between the control electrode and cathode of said second tube, and connections from said one of said resistances to said two other electrodes of said second tube to apply said potential therebetween as a firing potential.

WALTER LYONS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 25 Number I Name Date 2,011,927 Chireix Aug. 20, 1935 2,055,309 Ramsey Sept. 22, 1936 2,076,335 Dallenbach Apr. 6, 1937 

